The invention relates particularly to a staple coupling of the kind comprising interfitting male and female members for connection of hose within a fluid system, sealing means provided on at least one of the members to provide a fluid tight seal between the members and means to prevent separation of the members comprising external and internal circumferential grooves on the members respectively which register with one another when the members are engaged and holes on the female member to receive a staple, the holes being positioned and arranged so that when the staple is inserted into the holes the staple engages the registering grooves on the members to prevent separation of the members.
One example of such a staple coupling is described in British Pat. No. 1,253,981.
The prior art couplings provide a high measure of safety, and in most cases the higher the pressure within the coupling the more difficult it is to remove the staple from the holes. Removal of the staple at low pressures would require a low order of energy release, and whilst using a normal hydraulic medium even with a large quantity of stored energy from accumulators, the hazard of removing the staple is considered tolerable at pressures at which the staple can be removed.
However, with other fluid media such as hot hydraulic fluid, chemically dangerous fluids and gases, steam, etc., the potential hazards of release of the coupling whilst there is pressure inside the coupling has to be considered more carefully. For example, if one were to disconnect, large bore air hose from an air compressor receiver before complete air exhaustion, there would be considerable danger, particularly because of the possibility of "jet-flailing" of the hose.
The invention seeks to provide a more efficient locking means for a staple coupling.